Automatic elevator for dryer



Feb. 195 1957 E. A. HECKMAN ETAL 2,781,590

AUTOMATIC ELEVATOR FOR DRYER Filed June l2, 1953 n. QM.

ATTORNEY United States 'This invention relates 'to lan automatic Velevator sys- 'tern'"'and' particularlyto" Van elevator 'system 'wherein' -the elevator carriage automatically makes a number of Vtimed stops;` n'

The removal of moisture from articles by using commercialfdryers, "such as thoseernploying boiling tetrachlorethyl'ene, Ainvolves lthe' manual operations 'of krlowering fthe' water-wet articles into'the boiling' tetrachlorethyleiie'tank at 'the bottom of the dryer fora prescribed "period of time, raising 'the tetrachlorethylene soaked 1ar- Vticles -to a vapor region above the tank and holding them 'therefor another prescribed period of time and `finally raising"`them vabove the vapor region where they are held for another period of time to allow any condensed tetrachlorethylene -to evaporate, after which the dried -ar- 4ticles are removed from* the dryer.

vIt isjthe generalfobject ofthisk invention -to provide an elevator system for eliminating theaforementioned manual operations that will automatically and sequentially control .the positioningvof an elevator-carriage and hold the'"c'a`iriag'e Yat vitsY stops -for xedtime intervals.

Apreferred embodiment of the invention utilizes an automatic elevator system wherein the carriage Vis sus- 'pended "fromamo'for'drivensproekea a plurality ofllimit 'switches'"disposed'arouhdthe sprocket and their associated circuits control the carriage drive vmotor to sequentially position and hold the elevator carriage for fixed time periods at the different elevations as required 4for the operation.

These and other features of the invention will be more fully understood from the following detailed description taken in conjunction with the accompanying drawing in which:

Fig. 1 is a partially broken, elevational view of an elevator system according to the invention adapted to a commercial tetrachlorethylene dryer;

Fig. 2 is a detailed view of the chain sprocket and the limit switches of the device of Fig. 1, as seen from the backside of the sprocket of Fig. l; and

Fig. 3 is a schematic diagram of the control circuit of the elevator of Fig. l.

Referring now to Fig. l, a commercial tetrachlorethylene dryer 4 is provided with an elevator carriage S, shown schematically as a box but which may be of any construction convenient for carrying the articles to be dried, an elevator drive 6 and a control panel 7. The adjustable timers of the time delay relays, the control push button switches and the .on lamp are mounted on the control panel 7. The elevator carriage slides up .and down in the dryer 4 on the guide rods 8 and 48 and is suspended from a sprocket 9 by a chain 10. The sprocket 9 is driven by motor 11 through a gear reduction unit 12.

As shown in Fig. 2, three limit switches 13, 14 and 15 are mounted on the cover plate 18 for the elevator drive 6 and are disposed around the sprocket 9 which is provided with a pin 16 for actuating switches 13 and 15 and a cam 17 for actuating switch 14.

` atent L"Oil ce here# reb- Before discussingfthe control circuit `rfor lthe system, 'theQoperation of switch 14 will Ube described. -When the elevator carriage'S lis beingllowered and the [sprocket 9, as seenv inFifgZ," rotates clockwise, the' ilat/side'19 `of cam f17` engagesfrolleril) of switch 14 which is free to pivot counterclockwise about4 21 as shown in phantoni soy that' the cam "17 passes without actuatin'gfthe switch- 14 and theroller 20 is vreturned by a 'spring`to the-'position'shown kA's the elevator carriage jis" moved up, -and the sprocket V9 rotates counterclockwise,A the inclined surface 39 of `,the cam engages :the roller'l20 and forcesy it .outward radially ofthe sprocket'9thereby operating switch 14. i

' Referringv now to vthe circuit diagram of Fig. 3,'the voperation ofthe ysystem w-ill be described. After the articles to bedriedf'have been` placed onthee'levator carriage 5 shown in its starft or loading position '60 t Eig.f.f1),'.them .fdow'n button`22 is pushed, closing contacts 31 to energize the'down drive control relay y26 Afrom Vthe power vsource-23 through the normally closed contacts 27 of ,switch`11'3 thereby starting the motor 11 ,byl connecting itfto'the power source 23 through the contacts l24 and 25 of relay'26 to lower the velevator carriageH 5.' @Lock-up contactstlare provided on re- `lay`26 so thavtvonly a momentary energization is Vrequired to hold'the relay 26 operated. The operation of the down button 'also momentarily opensthe up" c1rcuit atcontacts 4310 release the np drive control relay 42 in ,the event `that it is in a locked-up condition otherwise the source 23 wouldbe short ycircuited if the contacts .40 vand il'were` closed when contacts-24 and As the motor .`11 `turnsthe sprocket 9 to lowerthe lelevator carriagel from the starting position 969 shown in Figfl, switch 15 is released to prepare the up circuit -by "closing contacts 32, contacts 50 being ,opened Ato de-energiz'e' the end'of cycle timer 33 whichcloses its contacts '38 to energize the` on lamp 34 indicating the Hdrying' cycle hasbeen started.

As the sprocket 9 continues to turn in the down direction, cam 17 engages the roller 20 of switch 14, but as previously described, the switch 14 is not actuated. When the elevator carriage has been lowered to the bath position 35 (Fig. l), it is stopped when pin 16 on the sprocket 9 actuates switch 13 whose contacts 27 open the motor energizing circuit by cle-energizing the "down drive control relay 26 to open contacts 24 and 25. Contacts 36 of switch 13 close to complete the energizing circuit for time delay relay 37. After its fixed time interval, relay 37 operates to close contacts 38 to energize the up drive control relay 42 through the closed contacts 32 of switch 15. Contacts 4i) and 41 of the motor energizing circuit close to connect the motor to the A. C. source 23, the polarity being reversed from that applied to the motor for driving the elevator carriage down. The motor thereupon drives the elevator up releasing switch 13 and opening contacts 36 thereon to de-energize time delay relay 37 which then opens its contacts 38. Relay 42, however, remains energized through contacts 32 of released switch 15, normally closed contacts 53 of switch 14 and lock-up contacts 52 of relay 42.

When the rising elevator reaches position 51 (Fig. l) in the vapor region of the dryer, cam 17 on the sprocket 9 actuates switch 14. Contacts 53 of switch 14 thereupon open and de-energize relay 42 opening contacts 40 and 41 to de-energize the motor. Time delay relay 55 is energized through contacts 54 of switch 14 and after its fixed time interval, contacts 56 close thereby energizing relay 57. Relay 42 is re-energized throughV the closed contacts 58 of relay 57 which re-starts the motor 11 to drive the elevator carriage up again. Switch 14 is thereupon released de-energizing time delay relay 55, but relay 57 remains energized through its lock-up contacts 59.

When the elevator returns to the starting position 60 (Fig. l), pin 16 on the sprocket 9 actuates switch 15 opening contacts 32 to de-energize relays 57 and 42 thereby opening the motor energizing circuit at contacts 40 and 41. Time delay relay 33 is energized through contacts 50 of switch 15 which, after` its lixed time delay interval, opens contacts 38 to extinguish lamp 34 indicating that the articles in the elevator carriage are dry and may be removed. t

Besides the automatic features of the invention, for convenience or emergency purposes, manual stop and up controls are provided on the control panel 7. When pressed, the stop button 61 opens the energizing circuits or the up and down drive control relays 42 and 26. When the up button 29 is pressed, contacts 28 are opened to de-energize the down drive control relay 26 and contact 62 of the up button closes the energizing circuit for the up drive control drive control relay 42.

The time delay relays used in this circuit, mounted on the control panel 7, are of a commercially available type having adjustable timers whereby the desired time in bath, time in vapor and linal evaporation time may be set.

It is to be understood that the above described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. An elevator system for an article dryer having a bath region, a vapor region above the bath region and an evaporation region above the vapor region said system comprising a carrier for the articles, a sprocket, a rotary driver for the sprocket, means for supporting the carrier from the sprocket, a pluralty of switches disposed around and controlled by the sprocket, a relay, means for controlling the relay to start the driver to lower the carrier to the bath region, means controlled by the switches for reversing the rotation of the driver to raise the carrier from the bath region through the vapor and evaporation regions and time delay relays controlled by the switches for sequentially stopping the driver to hold the carrier for predetermined and independently timed stops in the bath, vapor and evaporation regions.

2. A system for automatically and sequentially controlling the positioning of an elevator carriage comprising a rotatable member, a driver for the member, means for supporting the carriage from the member, a plurality of switches positioned to be operated in sequence by the rotating member, means for starting the driver to lower the carriage, means controlled by one of the switches for stopping the carriage in a given lowered position and initiating a timing cycle, means effective at the end of said cycle for starting the driver to raise the carriage and means controlled by another of the switches for stopping the upward travel of the carriage at an intermediate position.

3. An automatic system according to claim 2 in which manually controlled switching means are provided for stopping the driver at any position for the carriage and other manually controlled switching means are provided for interrupting the sequential positioning of the carriage and causing the driver to raise the carriage.

4. The combination with a rotatable member a carriage, means for supporting the carriage from the member and driving means for selectively rotating the member in opposite directions to lower and raise the carriage, of relays for controlling the rotation of the member, timing devices for disabling the driving means for predetermined time intervals and switches actuated by the member in dilerent positions thereof for selectively energizing the timing devices.

5. A system according to claim 4 in which one of the switches is adapted to be actuated only when the member is rotating in one direction to cause the carriage to stop at a predetermined position only when it is moving in a particular direction.

References Cited in the file of this patent 

